Rigid Welding Mask for Constant-Focus Laser Collector Welding

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Solution Overview

Problem

Laser welding of current collectors onto metal-ion electrochemical accumulator poles faces challenges due to manufacturing tolerances and vibrations, requiring a stable and robust weld seam with optimal focal distance maintenance across varying accumulator heights.

Innovation Solution

A laser welding device with a rigid solder mask connected to the laser head ensures a constant focal distance and optimal energy delivery, using a programmable optical focusing system and electrically insulating coatings to maintain weld quality and robustness, while compensating for height differences between accumulators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rigid welding mask connected to the laser head is used, then the focal distance remains constant and optimal energy delivery is ensured, but the device complexity increases

Engineering Contradiction:
Improvefocal distance consistencyVSAvoiddevice structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The welding mask is designed as a separate component with a specific geometric shape that defines a through passage for the laser beam. This segmentation allows the mask to be rigidly connected to the laser head while maintaining a constant focal distance, resolving the contradiction between manufacturing precision and device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The welding mask acts as an intermediary element between the laser head and the welding zone. Its rigid connection to the laser head ensures constant focal distance, while its geometric design (with bearing surfaces) allows it to mediate the pressure application to the workpiece without affecting the focal position.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the current collector is pressed against the pole to ensure stable welding, then weld quality improves, but the focal distance varies due to height differences between accumulators

Engineering Contradiction:
Improveweld stabilityVSAvoidfocal distance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The welding mask is designed with bearing surfaces that allow it to adapt dynamically to height variations between accumulators. The mask can be positioned at different heights while maintaining its rigid connection to the laser head, thus keeping the focal distance constant even when pressing against poles of varying heights.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system allows changes in the position parameter of the welding mask relative to the workpiece to accommodate height variations, while the focal distance parameter remains constant due to the rigid connection between the mask and laser head. This resolves the contradiction between weld stability and focal distance precision.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If elastic connection with springs is used to accommodate height variations, then adaptability improves, but the focal distance becomes variable and energy delivery is inconsistent

Engineering Contradiction:
Improveheight variation accommodationVSAvoidfocal distance consistency
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Instead of using an elastic connection that would allow focal distance variation, the invention segments the system into a rigidly connected laser head and welding mask assembly. The mask itself is designed with geometric features (bearing surfaces) that provide adaptability to height variations without compromising the rigid connection and constant focal distance.

Inventive Principle:
Principle #1Segmentation

4Stability of the object's composition

If the bearing surface extends continuously around the welding zone, then pressure distribution improves, but the device complexity increases

Engineering Contradiction:
Improvepressure distributionVSAvoidmask structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The welding mask is designed with bearing surfaces that have specific local qualities - continuous bearing surfaces in areas requiring pressure distribution, and open areas or different surface configurations in other regions. This local differentiation optimizes pressure distribution where needed while minimizing overall device complexity.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution achieves consistent, high-quality, and robust weld beads across varying accumulator heights, ensuring reliable electrical connections and mechanical strength despite vibrations, without the need for fine adjustments in support force.

Implementation Method 1

Laser welding is a joining technique that can be advantageously used to interconnect accumulators by welding the current collector to one pole of each of the accumulators

Methodology Applied
Scientific EffectLaser beam welding: Laser Beam Welding

Implementation Method 2

the laser head is directed towards a welding zone in which a weld bead is formed

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 3

the dimension of the welding mask in the direction of said beam, which defines the distance between the laser head and the welding zone, is constant, even when the mask exerts pressure on the welding zone. Throughout the welding process, the laser beam therefore has a constant focal distance, optimized to deliver the maximum energy to the welding zone

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP3774160B1Method and device for laser welding a first component to a second component
Publication Date: 2024.07.24 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3774160B1 patent drawingFigure 1
  • EP3774160B1 patent drawingFigure 2~3
  • EP3774160B1 patent drawingFigure 4~5B

AI summary

The invention relates to a method for laser welding a first component to a second component, comprising: - the placing of the first component (1) on the second component (2), - the application of a welding mask (4) comprising a flat contact surface (41) to the first component (1) in order to press said first component onto the second component (2), said welding mask (4) comprising a through-passage (43) for a laser beam, defining a welding area on the first component, the contact surface (41) at least partially surrounding said passage, - the emission a laser beam by a head (L) into said passage in the welding mask, in order to form a weld bead joining the first component to the second component in said welding area, said method being characterized in that the welding mask (4) is rigid and rigidly joined to the laser head (L), and in that the focal length (f) of the laser is constant, said constant focal length being ensured by said rigid mask.